The subs pragma is a red herring. Remove it, and the problem still holds.

The explanation is in the constant pragma, and some book I cannot remember explains that you should use () for constant-style sub calls because non_commutative * 10 parses as non_commutative(*10).

In reply to Re: Perl disproves commutativity of Addition/Multiplication by Anonymous Monk
in thread Perl disproves commutativity of Addition/Multiplication by syphilis

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